The invention is based on an electrical machine, in particular a brushless direct current motor or tacho-alternator in accordance with the type of the main claim. Such an electrical machine with a winding which is disposed in the air slot is known from DE-OS No. 25 11 567. In this described three phase arrangement, each phase of the winding is provided with at least two preformed coils which are equally distributed over the stator and are substantially uniformly designed and arranged in such a manner that in the circumferential direction, the head of the subsequent coil and phase is disposed above the preceding coil at the crossing point of the coil heads. A more uniform current distribution in the individual phases of the winding is obtained with such an overlapping winding arrangement than with a customary arrangement, in which the preformed coils are arranged in series in the circumferential direction. However, irregularities remain in the path of the induced voltage, which is particularly noticeable in a very disadvantageous manner during high rotational speeds or when using the induced voltage for measuring purposes in tacho-alternators. These fluctuations of the induced voltage and the current are substantially caused when the individual coil halves are penetrated by different flows due to their different distances with respect to the magnetic poles, so that the coil halves which are disposed closer to the magnetic poles have a higher induced voltage. When switching from one coil to another fluctuations and jumps occur in the picked up voltage of an alternator which should be eliminated.